1. Field of the Invention
The present invention relates to an image sensing device including a light-shielding film.
2. Description of the Related Art
An image sensing device including a plurality of photoelectric conversion portions is provided with a light-shielding film so as to define transit portions through which light (visible light) enters the corresponding photoelectric conversion portions. Thus, light is inhibited from entering undesirable portions. Japanese Laid-Open Patent No. 2001-284566 describes a sold-state image sensing device having an aluminum light-shielding film; FIG. 1 shows a passivation film 5 in contact with light-shielding film 4 and FIG. 2 shows a silicon oxide film 10 in contact with light-shielding film 4. Japanese Laid-Open Patent Nos. 2009-218374 and 2009-283482 describe image sensing devices having a light-shielding-pixel region having a copper light-shielding film.
A metal light-shielding film reflects light incident on the light-shielding film. The light reflected from the light-shielding film propagates in the image sensing device and, in some cases, enters some of the photoelectric conversion portions. A large part of the light reflected from the light-shielding film probably propagates through a film adjacent to the light-shielding film, and can enter the photoelectric conversion portions. If reflected light enters a photoelectric conversion portion, the photoelectric conversion portion may produce an undesired signal, that is, noise. This noise can adversely affect the resulting image.